Apparatus for dissemination of materials by implosion



April 1970 E. J. TICHAUER ETAL 3,505,957

APPARATUS FOR DISSEMINATION OF MATERIALS BY IMPLOSION Fiied Nov. 20,1967 v 2 Sheets-Sheet 1 F'Go I l6 Z9 INVENTORS.

47 ae/vssr .1 7701/41/52 smzvusr 4'. H11 #55 BY 0941550708 C OLE/V April14, 1970 E- J. TICHAUER ETAL 3,505,957

APPARATUS FOR DISSEMINATION OF MATERIALS BY IMPLOSION Filed Nov. 20,19672 Sheets-Sheet 2 Patented Apr. 14, 1970 3,505,957 APPARATUS FORDISSEMINATION OF MATERIALS BY IMPLOSION Ernest J. Tichauer, Santa Ana,Stanley G. Hughes, Palos Verdes, and Lambertus Coolen, Los Angeles,Calif., assignors, by mesne assignments, to the United States of Americaas represented by the Secretary of the Air Force Filed Nov. 20, 1967,Ser. No. 684,353 Int. Cl. F42]: 25/14 US. Cl. 102-6 1 Claim ABSTRACT OFTHE DISCLOSURE Wide dispersal of material is effected by detonatingsimultaneously a pair of spaced explosive charges adjacent to thematerial, one of the explosive charges being positioned above thematerial and the other smaller explosive charge being below thematerial.

In the conventional explosive dissemination of material, a singleexplosive charge is usually employed to break up the material and hurloutwardly the resultant particles thereof. Ordinarily, the force of theexplosion propels particles of material in all directions and aconsiderable amount' of the total explosive force is consumed in hurlingmaterial upwardly. Consequently, only a fraction of the explosive forceis effectively used to disseminate material laterally and the groundarea over which the material sprays is often relatively small.

Where a single explosive charge is used in disseminating a flammableliquid fuel, such as a hydrocarbon fuel employed in fire bombs, theforce of the explosion often creates an almost spherical cloud of fuelbefore ignition is achieved. Since the ensuing flame front passesquickly across the entire fuel cloud, the bulk of fuel is consumed in aball of fire before the droplets of fuel can settle. In most militaryapplications, however, it is preferred to disperse the fuel over a muchlarger area and effect combustion of the fuel nearer the ground.

Attempts have been made to effect wider dispersal of liquid fuels bysimultaneously detonating a pair of balanced explosive charges placedabove and below the container of fuel. By imploding the fuel in thismanner, a hemispherical cloud of fuel is formed which also burns as afire ball before settling of fuel occurs. Although combustion of thetotal mass of fuel occurs slightly nearer the ground when two suchexplosive charges are used, the ground area over which the fuel spreadsis not substantially greater than when only a single charge of the sametotal weight of explosive is employed.

It is therefore a principal object of the invention to provide animproved process of effectively using explosives to disseminatematerials.

Another object is to provide in a bomb structure an improved arrangementof explosives for disseminating materials by implosion.

Yet another object is to provide an improved fire bomb for creating alow lying cloud of liquid fuel over a relatively large area.

Still another object is to provide an improved bomb for thedissemination of solid materials over a wide area.

These and other objects and advantages of the invention will becomeapparent upon reference to the following description, drawings and claimappended hereto.

To attain the foregoing objects, it has been surprisingly found that thesimultaneous detonation of a pair of explosive charges, one above andthe other below the material, produces wide dissemination of thematerial when the top explosive charge is at least 1.1 times greaterthan the bottom charge.

In practice, the weight ratio of the top explosive charge to thebottomcharge is from about 1.1 to 1.7, preferably from about 1.2 to 1.5, morepreferably from about 1.3 to 1.4. The charges can be in the form ofrelatively thin plates or discs which cover both the upper and lowersurfaces of the container holding the material to be dispersed. Althoughan explosive charge of any shape can be used, it is preferred to employsymmetrical charges of uniform thickness. These explosive charges can bemechanically affixed to either the inside or the outside of thecontainer for the material, or else, bonded thereto by the use of aconventional adhesive.

Among the various materials which advantageously can be disseminatedaccording to the present invention are relatively frangible solids suchas naphthylene, acetyl benzyl peroxide, bismuth ethyl chloride, coal, aswell as non-frangible solid materials such as parafiins, magnesium, etc.Since the force of the explosion breaks up the frangible solids as theyare being dispersed, any desired size of such dispersed particles can beeffected by merely regulating the initial particle size and the size ofthe explosive charges.

The process of the present invention is particularly suitable for thedissemination of flammable liquid fuels such as benzene, alcohol,kerosene, jet fuel, gasoline and other similar petroleum hydrocarbons.Where such liquid fuels are used as in a fire bomb, they preferablycontain jelling agents such as polystyrene and isobutyl methacrylate aswell as metal soaps such a aluminum alkyls and aluminum arylalkyls.

Suitable explosives for the use herein can comprise mixtures of, forexample, trinitrotoluene, ammonium picrate, lead azide, pentaerythritoltetranitrate, cyclotrimethylene, trinitramine and other of the explosivecompositions disclosed in US. Patent 2,999,793 and 2,992,- 087, thedisclosures of which are incorporated herein by reference. Theseexplosives can be advantageously blended with an elastorneric materialsuch as poly isobutylene or polystyrene and/or a wax to yield anexplosive composition which is more easily cut, bent, and otherwiseformed into the desired shape.

With the fire bomb of the present invention, the particle size ofdispersed fuel which affects the duration of burning and the flametemperature can be controlled by regulating the charge to fuel ratio,i.e., the weight ratio of explosive to combustible fuel. In this way,the variation in the amount of explosive can be tailored to provide abomb for various intended purposes. In most applications, the charge tofuel ratio ranges between about .04 to .15, preferably between about .05to .12.

To effect optimum dispersal of the liquid fuel, the fuel container ispreferably formed of relatively light gauge material which can be easilyruptured. Suitable materials for the container are, for example, rolledaluminum or steel sheet. In a typical bomb, for example, an explosivedisc of pentaerythritol tetranitrate .500 inch in thickness is used witha bomb casing of aluminum .060 inch thick. Where an explosive disc isused on the outside of the casing, it is preferred to use a protectiveouter skin of thin gauge aluminum sheet. In case the explosive sheet ordisc is to be situated on the inside of the bomb casing, an interlinerof thin gauge sheet metal or synthetic resin sheet can be used as aprotective liner.

Although the liquid fuel container can, in general, be of any desiredshape, it is preferred to use a fuel tank tailored in length to bestsuit the particular application. With the generally right circular fueltank, optimum radial dissemination of the fuel is obtained using a ratioof length to diameter of about 1:1. In cases where a large fire ball isdesired, other shapes can be employed such as a spherical fuel tank.

Bombs constructed according to the present invention can also beemployed to disperse various of the liquid chemical agents which producea toxic or irritating physiological effect, a smoke screen, anincendiary action other than a fire bomb effect, or a combination ofthese effects.

The invention will be illustrated further in the accompanying drawingsin which:

FIG. 1 is a perspective view of the several components making up a firebomb, the principal components being shown in their relative position;

FIG. 2 is a fragmentary view taken along line 22 of FIG. 1, showing anenlarged cross section of one of the fuel expansion chambers;

FIG. 3 is a top view of the fire bomb of FIG. 1, illustrating thearrangement of the three expansion chambers and the booster assemblyshown in dotted lines;

FIG. 4 is a side elevational view of the assembled fire bomb of FIG. 1,showing in partial broken sections the fuze and the booster assembliesconnected thereto;

FIG. 5 is a fragmentary view taken along line 55 of FIG. 3, showing anenlarged cross section of the fuel loading port;

FIG. 6 is a fragmentary view taken along line 66 of of FIG. 4, showingan enlarged cross section of the fuze assembly;

FIG. 7 is a fragmentary view taken along line 77 of FIG. 4, showing thepropagating cord sleeve;

FIG. 8 is a fragmentary view taken along line 8-8 of FIG. 4, showing inan enlarged cross section the connection betwen the skirt and the lowerstabilizer plate.

Referring now to the drawings, the bomb structure shown in FIG. 1comprises a generally cylindrical fuel tank assembly 5 with a pluralityof expansion chambers 11 connected thereto, an outer housing or skirt21, a top protective cover assembly 33, a resilient cushion 43, and abottom counterweight or stabilizer plate 47. The fuel tank assembly 5consists of a relatively thin walled cylindrical metal shell 6 withflanged and reinforced flat heads 7 welded at each end thereof (FIG. 2).

Three pairs of expansion fittings, a bottom fitting 12 and a top fitting13 are Welded to the cylindrical tank shell, each pair of such fittingsbeing connected by an elastic expansion tube 11 formed from a materialinert to the fuel in the tank. The tube 11 can be advantageously formedfrom flexible polymers or copolymers of polyvinyl chloride, and othersimilar elastic synthetic resins. Clamps 15 are secured about the tubeat each end thereof to efiect a liquid seal between the tube and theexpansion fitting. Each of the top fittings 13 are provided with athreaded vent screw 16, an associated sealing washer 17, the vent screw16 being removed to permit escape of entrapped air when the tank isbeing filled. The flow of both fuel and gases between tank 5 andexpansion tubes 11 is facilitated by passage 18 formed in expansionfittings 12, 13.

Fuel is introduced into tanks through fill fitting 19 which can beclosed by pipe threaded filling plug 20 (FIGS. 1, 3, and 5). Should theambient temperature rise causing the volume of fuel to increase becauseof the change in density, fuel in the filled fuel tank flows throughpassage 18 into the flexible tube 11 which expands to accommodate theincrease in fuel volume. Due to the resistance of the elastic tubes tosuch dilation, the internal pressure of fuel rises which can causeslight bulging deformation of flat heads 7.

The skirt 21 comprises a relatively thin sheet metal housing, square incross section having rounded corners, the four sides of the skirt beingtangent but not mechanically attached to the cylindrical fuel tank 5.The skirt is sufliciently longer than the fuel tank to permitinstallation of the cover assembly 33, cushion 43, and base plate 47(see FIGS. 1 and 4).

An impact mechanical fuze can be screwed into a flanged and internallythreaded fuze seat 22 which can be attached to the skirt 21 at about themid length of the skirt below filling fitting 19. Although any of theconventional impact type mechanical fuzes can be used, it is preferredto employ an omnidirectional fuze of the delayed arming and instantacting type. Attached to the inner end of the fuze seat 22 is a lead outassembly 23 which consists of a disc of sheet type explosive material 24in close proximity to the output end of the fuze 25 and the respectiveends of two equal lengths of detonating cord 26.

The other ends of the detonating cords 26 are connected to boosterassemblies 27, 28 attached, respectively, to the upper and lowerexplosive charges 29, 30 (FIGS. 2, 4, and 5 These booster assembliesshown in dashed lines in FIG. 3 comprise a detonator'and booster charge31 encased within a plastic housing 32. In a preferred embodiment shownin FIG. 4, relatively thin cushion pads 34, 34 (FIGS, 2 and 4) lie onthe upper and lower surfaces of top explosive charge 29.

Intermediate the bottom head 7 of tank 5 and the lower explosive charge30 is another cushion pad 37, the lower surface of charge 30 resting ona relatively thick resilient cushion 43. A groove 35 is formed in anupper surface of cushion 43 for the lower detonating cord 26, and a hole44 is cut in this cushion to accommodate booster assembly 28. Aconventional adhesive can advantageously be used to secure theassemblies 27, 28 to the respective explosive charges. A protectivesleeve 36 surrounds the detonanng cord 26 where it bends around thecorners of tank 5 (FIG. 7).

A relative heavy metal base plate 47 is secured to the lower end of theskirt 21 by means of countersunk, fiat headed machine screw 49 (FIG. 8).Because of the relative thickness of the skirt, the skirt metal isdimpled, or swaged, into the oversized countersunk bore in the baseplate, to provide a flush exterior.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions. Consequently, such changes and modifications are properly,equitably, and intended to be, within the full range of equivalency ofthe following claim.

What we claim is:

1. A device for disseminating flammable liquid materials by implosionwhich comprises:

a container for the flammable liquid to be disseminated;

an explosive charge on both the top and bottom of said container, thecharge above the container being at least 1.1 times larger than thecharge below the container;

at least one elastic expansion tube connected to and communicating withsaid container to permit the flow of said flammable liquid from saidcontainer into the expansion tube, thereby preventing rupture of saidcontain-er when said flammable liquid fuel expands;

a fuze to initiate simultaneous detonation of both explosive chargeswhereby to redirect the upward blast force and eifect wide lateraldispersion of said flammable liquid materials.

References Cited UNITED STATES PATENTS 1,287,372 12/l9l8 McGaw 102-662,535,309 12/1950 Mari 102-34.4- 2,586,801 2/1952 Epler et al. 10263,382,800 5/1968 Biggs 1026 SAMUEL W. ENGLE, Primary Examiner US. Cl.X.R. 10266,

